The invention relates to an unloading flap of a stationary or mobile silo for pourable particulate material having at least one outlet opening, said unloading flap comprising an upper part that is secured to a first silo wall and a lower part that hinges on the upper part and can be tilted into the open and closed positions by means of an actuating rod that can be power driven.
Silos, both stationary and mobile silos (on lorries and railway trucks) that hold pourable particulate material must feature outlet openings that are sealed off effectively when closed, which is not simple because of the tendency for long edges to sag. Closure flaps of the conventional kind can be secured by the actuating rod only at both ends of the lower sealing edge, and must therefore be constructed such that they are extremely rigid in order that,when the flap sags under load, the gap at the sealed edge of the flap is smaller than the diameter of the particulate material. Also known, in the case of longer flaps, is to provide a plurality of securing points distributed along the length, for example 4-6 cams which are pressed against the silo wall by a camshaft. By turning the camshaft all closure means can be opened simultaneously, causing the plate to tilt into the vertical position and allowing the particulate material to run out.
Described in the U.S. Pat. No. 3,717,110 are motor driven unloading flaps for a silo type of container, in which the said flaps can be tilted towards each other into the closed position and away from each other into the open position. Each of the two flaps comprises an outer and an inner section featuring floor panels that form the silo wall when in the closed position. The individual flaps are combined by means of extrusion type components to form box-shaped construction elements.
On opening the closure flaps both parts of the same are brought from the straight into an angular position, thus exposing the silo outlet.
The lower edge of one of the two closure flaps features a tongue, and a closure plate directly adjacent and vertical to the closure flap features an opening at the end. In the closed position of the both closure flaps a locking mechanism tilts an engaging hook into the opening and fixes the other closure flap onto the tongue.
The closure mechanism and the element for actuating the closure flap are centrally actuated by a piston; as a result this makes it necessary to have a complicated lever system with numerous deflections of forces.